Introduction - If you have any usage issues, please Google them yourself
The realization of graphics drawing a straight line, park and circular arc and straight line cutting, filled with features such as region 1 to draw a straight line, only need to know the starting point and end point can be. Press the mouse in the working interval (i.e. choosing starting point), drag to another release (the end), that is to be a straight line. The 2 circle center coordinates and radius, need, start angle and end angle, as far as the experimental requirements of painting 1/4 arc, can set the starting angle end angle =0, =45, to draw the entire arc starting angle and termination angle are respectively 0 and 360 can be. More parameters need 3 elliptic, with ellipse center coordinates, long axis, short axis, long axis and the positive X axis angle, and the initial eccentric angle and termination of centrifugal angle, to draw the whole or part of the ellipse ellipse only need to control the initiation and termination of eccentric angle. Similar to an arc, a specific descript